MUC1 and non-small cell lung carcinoma: Additionally, when MUC1 is blocked, the PI3K–mammalian target of rapamycin pathway is downregulated.21 Furthermore, MUC1 knockdown in A549/PTX cells showed reduced PTX resistance, PI3K signaling and stemness, suggesting that an increase of CSC properties is associated with PTX resistance and MUC1-C expression in NSCLC.